import java.util.ArrayList;


public class Stack<E> {
	
	private ArrayList<E> list;
	public Stack()
	{
		list = new ArrayList<E>();
	}
	
	public E pop()
	{
		return list.get(0);
	}
	
	public void push(E e) {
		list.add(e);
	}
	
	public boolean isEmpty()
	{
		return list.isEmpty();
	}
	
	public int size()
	{
		return list.size();
	}

}
